DB_ENV->set_mp_max_write()

#include <db.h>

int
DB_ENV->set_mp_max_write(DB_ENV *env, int maxwrite, 
                         db_timeout_t maxwrite_sleep); 

The DB_ENV->set_mp_max_write() method limits the number of sequential write operations scheduled by the library when flushing dirty pages from the cache.

The database environment's maximum number of sequential write operations may also be configured using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_mp_max_write", one or more whitespace characters, and the maximum number of sequential writes and the number of microseconds to sleep, also separated by whitespace characters. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

The DB_ENV->set_mp_max_write() method configures a database environment, not only operations performed using the specified DB_ENV handle.

The DB_ENV->set_mp_max_write() method returns a non-zero error value on failure and 0 on success.

Parameters

maxwrite

The maximum number of sequential write operations scheduled by the library when flushing dirty pages from the cache, or 0 if there is no limitation on the number of sequential write operations.

maxwrite_sleep

The number of microseconds the thread of control should pause before scheduling further write operations. It must be specified as an unsigned 32-bit number of microseconds, limiting the maximum pause to roughly 71 minutes.

Errors

The DB_ENV->set_mp_max_write() method may fail and return one of the following non-zero errors:

EINVAL

An invalid flag value or parameter was specified.

Class

DB_ENV, DB_MPOOLFILE

See Also

Memory Pools and Related Methods